Chamber Nested Bolt and Oval Rifling

ABSTRACT

A means of keeping the cartridge in the chamber during the firing sequence until the peak pressure drops to a safe level by nesting the bolt into the chamber with the cartridge. The bolt and cartridge will form a gas seal and recoil backwards when the gun is fired, but the chamber walls will support the cartridge while it recoils backwards until it exits. The gun will be designed so that it does not exit until the pressure drops to a level where the cartridge can withstand the force. Doing this will allow the gun to utilize high pressure ammunition without requiring complicated locking and/or delay mechanisms currently used. This will decrease the initial cost of manufacturing the gun, improve accuracy and reliability, and reduce the peak recoil felt from the gun. Also spinning a projectile by using an oval cross section where the major and minor axis rotates around the center of the oval eliminates the need for groves and polygonal rifling. This will increase the efficiency and the precision of the gun.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefits of provisional patent application No. 62/674,015 filed 2018 May 20 by the present inventor.

FEDERALLY SPONSORED RESEARCH

Not Applicable

SEQUENCE LISTING OR PROGRAM

Not Applicable

BACKGROUND Field

This application relates to a novel recoil operated system that simplifies the construction of guns while improving their accuracy and reliability and improving the accuracy of the barrel by utilizing a oval barrel cross section that rotates around its major and minor axis to to cause the projectile to spin.

Prior Art

For the remainder of this patent, a gun refers to any tube from which bullets, shells, or other missiles can be propelled by gas pressure. The gasses can be generated with a high pressured tanks, chemical reactions, or other methods. Simple blowback guns are less expensive to manufacture and more reliable, but can not currently be used with guns designed to shoot high pressured ammunition or large projectiles. The alternative to using simple blowback guns is using gas operated cycles or delayed blowback mechanisms, but this complicates the design of the gun. The increase in complexity increases the cost to manufacture the gun, the likelihood that the gun malfunctions, and, in some cases, can decreases the accuracy of the gun.

One alternative to the increased complexity of cycling the gun is firing from an open bolt which is also sometimes called advanced primer ignition. In this design, the bolt is held open until the trigger is pulled. When the trigger is pulled, the bolt is pushed forward carrying the projectile towards the chamber. Once the projectile and the bolt are inside the chamber, the projectile is fired. The bolts forward momentum allows the peak pressure to drop before, bolt is pushed backwards. The remainder of the projectiles momentum is used to cycle the bolt.

This design is theoretically wonderful, but it is difficult to implement. One problems is that the bolt must be designed around a specific type of ammunition, limiting the flexibility of the gun. The main drawback, however, is the timing of the ignition of the projectile. Very slight differences in ignition will cause different recoil, resulting in poor grouping. This design also does not anticipate hangfire (where the projectile experiences a delay between when the trigger is pulled and when the propellant ignites). When this occurs, open bolt guns reverts to a simply blow back system with an inadequate slide mass and spring force creating a dangerous situation for the shooter, and the possibility that the gun is damaged.

Due to the challenges presented with timing, the open bolt design is only currently used with low pressure ammunition in sub machine guns such as the Uzi. The one exception to this is a Germans built 30 mm cannon that was designed during World War II. After the War, the US Army determined it was not a suitable design.

Rifling has traditionally consisted of lands and grooves. When the projectile is fired, the lands cut into the projectile, and force it to spin as it travels down the barrel. While the spin is invaluable for stabilizing the projectile, the act of cutting the projectile with the lands causes numerous problems with interior and exterior ballistics. The lands are slowly worn away by the projectile, causing the barrel to lose accuracy over time.

Additionally, creating a seal between the lands and groves is difficult which allows gas to leak out. The lands also rapidly deform the projectiles, resulting in copper or lead build up and creating tremendous amounts of friction inside the barrel. This friction causes the projectile to have a lower velocity, and causes the barrel to distort decreasing the accuracy and power of the gun.

Once the projectile exits the barrel, the deformations interact with the air, increasing the air resistance experienced by the projectile. This causes the projectile to experience a more rapid deceleration for it's angular and linear velocity. The deceleration causes a decrease in energy in the projectile and an increase in flight time. The increase in flight time increases the deviation caused by the wind and causes a larger projectile drop. It also causes the angular velocity of the projectile to decrease more rapidly. This introduces a gyroscopic drift (also known as spin drift), which causes a larger circular error probability.

Polygonal rifling attempts to solves these problems by replacing the lands and groves with more minor deformations (commonly referred to as hills and valleys) that are in a polygonal pattern (normally a hexagon for small bore or a octagon for large bore guns). By having the polygon rotate about its center, the projectile is forced to spin. Since there are no sharp edges, the friction is reduced inside the barrel. This allows the projectile to have more energy when it exits the barrel. Once the projectile exits the barrel, since the deformations on the projectile are smaller, the projectile experiences less air resistance once it exits the barrel.

The primary challenge of polygonal rifling is creating an effective seal and eliminating fouling inside of the barrel. It is difficult to create a seal with polygonal rifling due to the non circular cross section of the shape. In modern polygonal rifling, they commonly round the angles and the lines in a attempt to improve the seal. Fouling is also an issue due to the difficulty of creating a smooth transition from a circular cross section in the chamber to a polygonal cross section in the barrel. The deformation of the projectile by the polygonal rifling also causes the projectile to experience higher levels of deceleration then would be experienced by a cylindrical object.

SUMMARY

This application relates to improving guns by incorporating a bolt that is nested inside the chamber prior to firing and utilizing an oval cross section where the major and minor axis rotate about the center to replace rifling. By incorporating a bolt that is nested inside the chamber of the gun prior to firing the gun, the bolt will not have to be locked for the chamber to support the cartridge while the pressure is at an unsafe level. The cartridge will immediately recoil rearward when the gun is discharged, but since it is inserted forward in the chamber, it will remain supported by the chamber walls until the pressure drops to a safe level. Doing this will allow the gun to utilize ammunition that operates at higher pressures than simple blowback guns can accommodate without the added complexity required for a gun to function with advanced primer ignition, delayed blowback systems, blow forward systems, or gas operated recoil. This will allow the gun to be simpler (reducing the price and maintenance), and will improve the guns performance.

Further accuracy improvements can be obtained by using a barrel that rotates the projectile inside by deforming its cross section from a circle into a oval shape and then rotating the major and minor axis of the oval as it travels down the barrel. This will replace the grooves and lands currently used with traditional rifling and the hills and valleys used with polygonal rifling. Since an oval is the closest shape to a circle, the distortion of the projectile will be minimized. This will allow it to create the best seal possible between the projectile and the barrel. It also allows the projectile to have the lowest possible surface area in contact with barrel. This will result in less friction inside of the barrel and less air resistance once the projectile exits the barrel. The decrease in friction inside the barrel will result in a higher muzzle velocity and a longer barrel life. The decrease in projectile deformation will also decrease the projectile's air resistance once it exits the barrel. Since the projectile is no longer experiences as much air resistance it will have more kinetic energy when it reaches its destination, experience less drop, wind drift, and gyroscopic drift.

An additional advantage is that the transition from the circular chamber cross section to the barrel oval barrel cross section can also be gradual. This will decrease fouling inside the barrel and increase the consistency of the projectiles. The gradual transition and the smooth shape of the oval can also allow the use of delicate projectiles (such as paintballs). The projectiles could also be manufactured as ovals so that they require an even lower amount of deformation when being fired. This would eliminate the need for a transition.

DETAILED DESCRIPTION

FIG. 1 represents the most basic concept of a chamber nested bolt. The bolt carrier (1), the cartridge (2), and the bullet (3) are at rest prior to firing nested inside the chamber of the firearm. The bullet is at the end of the camber (4) protruding into the barrel (6), and the bolt carrier's end is also located inside of the chamber so that when it recoils backwards, the gas is not instantly released. A spring or other return force (5) is holding the bolt carrier shut until the firearm is fired. A receiver (9) holds the bolt in place while it is at rest, and guides it when it recoils.

In addition to the return force (5), the firearm can incorporate additional means of controlling the speed of the bolt's recoil. This could be done using a damper or dashpot, but many devices are suitable for controlling the bolt's recoil after firing. By including a delayed blowback devices (such as gas operated cycles or delayed blowback so that the speed of the bolt's recoil could be modified) For the sake of simplicity, individual illustrations will not be included for all of these methods, but they can easily be envisioned by someone skilled in the arts.

In FIG. 2, the bullet (23) has been fired, and is traveling down the barrel (26). The bolt carrier (21) and the cartridge (22) are sliding backwards as the bullet (23) travels forward. Due to the larger mass of the bolt carrier (21) it accelerates much slower than the bullet. The bolt carrier (21) motion is slowed by the return force (25) and any device installed in the fire arm to help control it. The chamber (24) remains closed due to the bullet (23) blocking the gas from escaping from the front, and the cartridge (22) and the bolt (21) blocking the gas from escaping from the rear. The receiver (29) guides the bolt carrier (21) when it is in motion and decelerate it.

In FIG. 3, the semi automatic configuration is shown. The bolt (31) may be designed so that it remains shut until the bullet exits the barrel (36), or the bolt may be designed so that it remains shut until the pressure inside the chamber (34) has dropped to a safe level. The firearm can be reloaded through any common action including bolt, pump, semi-automatic, and fully automatic. If the firearm is designed to work in a semi-automatic or fully automatic configuration, the bolt recoils far enough back for it to feed a new cartridge (38) and bullet (37) into the chamber. The return force (35) pushes the slide back into the firing position.

FIG. 4 depicts the cross section of a barrel that is an oval instead of a circle. On the left side of the image (61), the major axis of the oval is vertical, and the minor axis is horizontal. On the right side of the image (62) the major axis of the oval is horizontal, and the minor axis of the oval is vertical. This would force the projectile to rotate 90 degrees The transition of the axis can be done at a constant or varying rate as it travels along the barrel based on the preference of the designer.

To minimize fouling, a gradual taper can be incorporated between the chamber, which is circular and the barrel which is oval. In the tapper, the major axis increases and the minor axis decreases.

DRAWINGS—FIGURES

FIG. 1. Illustrates a gun with a nested bolt, a cartridge, and a projectile, in the chamber prior to the gun firing.

FIG. 2. Illustrates a gun immediately after it is fired. The nested bolt is moving towards the rear, and the projectile is traveling forward. The nested bolt is still in the chamber, trapping the gas in the barrel and the chamber.

FIG. 3. Illustrates a gun after the nested bolt has exited the chamber, and the cartridge is ejected.

FIG. 4. Illustrates a barrel that is oval instead of circular. By rotating the major and minor axis of the oval, the projectile will be forced to spin as it travels along the tube. The rate of the projectile spin can be adjusted by the rate at which oval rotates inside of the barrel.

ADVANTAGES

From the description above, a number of advantages are evident:

-   -   a. By utilizing a Nested Bolt in the Chamber, without a locking         and/or delay mechanism, the production of the guns will be         simpler.     -   b. By utilizing a Nested Bolt in the Chamber, without a locking         and/or delay mechanism, the number of parts will be reduced         leading to a more reliable, accurate gun.     -   c. By utilizing a Nested Bolt in the chamber, with a locking         and/or delay mechanism, the locking and/or delay mechanism can         be constructed with lower tolerances. This will make them         simpler and more reliable.     -   d. By utilizing a Nested Bolt in the Chamber the recoil force         will be distributed over a longer time, decreasing the maximum         recoil force.     -   e. By utilizing a barrel with an oval cross the manufacturing of         the barrels will be simplified since less material will need to         be removed.     -   f. By utilizing a barrel with an oval cross section, the         projectile will have less area in contact with the barrel and a         superior seal.     -   g. By utilizing a barrel with an oval cross section the         distortion to the projectile is minimized creating a smaller         force of friction inside the barrel, less distortion of the         barrel, and a more aerodynamic projectile.     -   h. By utilizing a barrel with an oval cross section, a gradual         transition between the chamber and the barrel is easily         accomplished diminishing fouling.     -   i. By utilizing a barrel with an oval cross section and a         gradual transition, a delicate projectile, such as a paintball         can be used.     -   j. By utilizing a barrel with an oval cross section, the         projectile can reach higher velocities without damaging the         barrel.

CONCLUSION RAMIFICATION AND SCOPE

Thus the reader will see that by utilizing a nested bolt in the chamber, it is possible to build a reliable gun with fewer parts that can still utilize high pressure ammunition. There are multiple alternative methods that could be adjusted to meet different scenarios. This design can be used independently of or in addition to other delayed/retarded blowback designs including off axis bolt travel, screw delayed, etc. By utilizing an oval cross section where the major and minor axis rotate the benefits of rifling will be maintained while significantly improving the accuracy, speed, and barrel life of the gun.

While the above description contains specifications and examples, these should not be construed as limiting the scope of any embodiment, but as an exemplification of the presently preferred embodiments thereof. Many other ramification and variations are possible within the teachings of the various embodiments. Thus the scope of the invention should be determined by the appended claims and their legal equivalents, and not by the examples given. 

1. A gun comprising: a. a barrell; b. a chamber that is longer than the cartridge; c. a bolt/carrier unit that is partially or completely nested inside the chamber prior to the cartridge being fired;
 2. A barrel comprising: a. a oval cross section that forces the projectile to spin by rotating the major and minor axis;
 3. A gun as set forth in claim 1 that utilizes a existing methods of recoil control in addition to the nested bolt:
 4. A gun as set forth in claim 1 that fires from a open bolt or partially open bolt:
 5. A gun as set forth in claim 1 that utilizes a closed bolt configuration:
 6. A gun as set forth in claim 1 that utilizes a damper or a dashpot to control the rate of recoil and return of the nested bolt:
 7. A gun as set forth in claim 1 that can operate in a single shot, semi-automatic, or fully automatic configuration:
 8. A gun as set forth in claim 1 that incorporates part of the chamber with the bolt carrier unit to increase the mass of the slide:
 9. A gun as set forth in claim 1 that uses the friction generated between the cartridge and the chamber during blow back to slow the bolt:
 10. A gun as set forth in claim 1 that has deformations on the surface of the chamber to increase the friction between the chamber and the cartridge:
 11. A barrel as set forth in claim 2 that utilizes gain twist rifling to distribute the torque over a longer period:
 12. A barrel as set forth in claim 2 that utilizes freebore:
 13. A barrel as set forth in claim 2 that utilizes a gradual transition between the chamber the oval barrel:
 14. A barrel as set forth in claim 2 that utilizes a oval shaped chamber in addition to a oval shaped barrel:
 15. A barrel as set forth in claim 2 that utilizes projectiles with an oval cross section to minimize deformation:
 16. A barrel as set forth in claim 2 that can fire delicate projectiles:
 17. A barrel as set forth in claim 2, that can fire hypersonic projectiles with a twist without damaging the rifling:
 18. A barrel as set forth in claim 2 where the cross section is a ellipse: 